Can One Lake Be Everything to Everyone? The
Challenge of Managing Lake Okeechobee for
Multiple Users
Susan Gray, Ph.D.
South Florida Water Management District
Lake Okeechobee Characteristics
Surface Area ~730 square miles
Mean depth ~8 ft, Maximum depth ~18 ft
Natural lake, but now impounded
Regulated Stage
Phosphorus enriched open water zone
High turbidity due to sediment resuspension
Many ecological and societal values
2
3
4
Inflows & Outflows – Inflow capacity
exceeds outflow capacity
Taylor Creek
Kissimmee
Nubbin Slough
C-41, C-40 and
C-41A
Fisheating Creek
(uncontrolled) and
C-5A
S-135
S-308; when
stage <14.5 may
flow back to
Lake
Lake
Okeechobee
C-10
S-77
Discharges are
80% west and
20% east
S-354
S-352
S-351 S-2 and S-3 under high rainfall
may pump back to Lake
5
2004 and 2005 Hurricane Tracks
Jeanne
Wilma
Ivan
S133
10/24 11:00 AM
105 mph
NE ~25 mph
S135
S131
Charley
Frances
S4
S352
10/24 9:00
AM
110 mph
NE ~25 mph
6
7
8
SEICHE AND LAKE LEVELS
Near-term hurricane impacts were primarily
due to wind/wave interactions
Long-term hurricane impacts due to resuspension of lake sediments and nutrient
loads from high rainfall events
Lake levels increased by approximately 6 feet
due to the 2004 hurricanes and
approximately 1.5 feet from Hurricane Wilma
High lake levels, coupled by storm surge and
dry season frontal systems continued to keep
sediments in suspension for many months
9
Wave Erosion From Hurricane Wilma
10
Other in-Lake impacts
Missing bulrush near Observation Shoal
New cut north of Cochran’s Pass
Uprooted vegetation near Belle Glade
Bloom near Clewiston
11
K in g s B a r
N o r th
T in H o u s e
C ove
O k e e W a te r
In ta k e
T a y lo r C r e e k
Lock
M o u th o f
K is s im m e e
In d ia n P r a ir ie
C anal
F is h E a tin g
B ay
C le w is to n
o ffs h o r e
s e c c h i d e p th m .
TRANSPARENCY
1.2
1
0.8
Pre hurricanes 2004
0.6
Pre Wilma
Post Wilma
0.4
0.2
0
12
13
St. Lucie Estuary Salinity Envelope
Salinity Envelope
Surface and Bottom Mean Daily Salinity at Roosevelt Bridge
35
30
Data provisional and subject to change
Salinity (ppt)
25
20
15
10
5
001/01/05
03/01/05
05/01/05
07/01/05
09/01/05
11/01/05
01/01/06
03/01/06
US1 surface daily mean
30 day prior US1 surface daily mean
05/01/06
07/01/06
09/01/06
11/01/06
01/01/07
03/01/07
05/01/07
US1 bottom daily mean
30 day prior US1 bottom daily mean
14
Daily Salinity in the Caloosahatchee Estuary and S-79 Discharge
23000
22000
21000
20000
19000
18000
17000
16000
15000
14000
13000
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
1/1/2005
40
30
25
20
15
(parts per thousand)
35
Salinity
Freshwater Flow
(cubic feet per second)
S-79 flow
Near Surface Salinity (~1.0 m ) at Ft. M yers
Near Surface Salinity (~1.0 m ) at Shell Pt.
10
5
0
5/1/2005
9/1/2005
1/1/2006
5/1/2006
9/1/2006
1/1/2007
5/1/2007
15Y2007
W
Lake Okeechobee Water Depth Comparison
http://spatial1.sfwmd.gov/losac/sfwmd.asp
Elevation
14.3 ft, NGVD
Long-term
Average
(1965-2005)
Elevation
8.82 ft, NGVD
Record Low
02-July-2007
Elevation
17.0 ft, NGVD
H. Wilma
Nov-2005
Elevation
12.7 ft, NGVD
Start of ’07
dry season
01-Nov-2007
Elevation
10.1 ft, NGVD
20-Feb-2008
16
17
Dry Conditions - North
18
Dry Conditions - West
19
Dry Conditions - South
20
21
22
Low Lake Stage Project Locations
24
25
Forward Pumps - BODR
Phase II
Temporary
Forward
Pumps for Water
Supply
C10A
S352
February 5, 2007
26
Temporary Forward Pumps
Cost $1.5 million (already purchased)
1400 cfs capacity
Deliveries to the south only
Meets 45 % cutback in agricultural
users to a Lake elevation of 7 ft.
This demand met for all but 4 weeks
under extreme drought
Investigating upgrade potential
27
Challenges re. Lake Stage
Efforts to manage stage to benefit of lake
health must take into consideration other uses
of the resource (e.g., water supply for human
and environmental needs)
Present lack of alternative regional storage
locations
Impacts of lake regulatory discharges on
downstream ecosystems (St. Lucie Estuary,
Caloosahatchee Estuary, Everglades Protection
Area)
Extreme highs and lows an ecological concern
29
The Solution
Northern Everglades Program
Phase II of the Lake Okeechobee
Construction Project Technical Plan
submitted to the Legislature February 2008
Outlines a phased approach to water
quality and water quantity improvements,
using a combination of source and regional
projects, including public/private
partnerships.
Defines storage needs as a range from
900,000 to 1.3 million ac. ft.
30